Devices and weapons using delayed priming



April 14, 1970 J. VILBAJO DEVICES AND WEAPONS USING DELAYED PRIMING z Sheets-Sheet 1 Filed Feb. 8, 1968 INVFNTOR. j. V L I b a 0 BY g gzczx ATTOYLNEBS J. VILBAJO April 14, 1970 DEVICES AND WEAPONS USING DELAYED PRIMING 2 Sheets-Sheet 2.

Filed Feb. 8, 1968 Fry 5 4,- 5 a 5 c L1- a Ir a F 2 I. i. Q I f n P l 0 m p INVENTOR. J. V52 29 ago ATTO r: N E55 United States Patent 3,505,958 DEVICES AND WEAPONS USING DELAYED PRIMING Jean Vilbajo, Brussels, Belgium, assignor to Contigea, Societe Anouyme, Brussels, Belgium, a body corporate of Belgium Filed Feb. 8, 1968, Ser. No. 704,038 Claims priority, application Belgium, June 27, 1967, 700 545 Int. Cl. F42b 5702; F41f 3/02 U.S. Cl. 10238 3 Claims ABSTRACT OF THE DISCLOSURE DESCRIPTION OF THE INVENTION This invention relates to a method for priming a charge disposed in an enclosure by the combustion of another charge disposed in another enclosure contiguous to the first enclosure. This method is characterized in that it comprises feeding, with expansion, a small portion of the combustion gas of the said second charge into an intermediate enclosure disposed between the said two enclosures and allowing the pressure within said enclosure to increase progressively to the duly predetermined rupture pressure of one of the walls of the said intermediate enclosure, this rupture bringing the said two enclosures into direct communication, thereby allowing the firing of the first charge by the gases resulting from the combustion of the second charge.

This invention relates also to a very simple device for carying out this method, said device consisting substantially of an expansion chamber, a wall of which is provided with a locked opening, while another wall has a duly established rupture coefficient to pressure lower than that of the other walls of said chamber.

The method according to the invention and the device for carrying out said method may be advantageously used in various fields, but more particularly in armaments. In the latter, the invention may be applied in ammunitions for anti-tank guns of the type comprising a gun and a support allowing the recoil of the said gun, the said ammunition being provided with a counterrecoil charge.

It is thus only by way of illustration and without any limitation that this particular embodiment of the invention is described hereafter in detail, reference being made to the enclosed drawings in which:

FIGURE 1 is a front view with partial sections of a light anti-tank gun, the weapon being shown in firing position;

FIGURE 2 is a front view with a partial section of an ammunition for the weapon represented in FIGURE 1 and conditioned for carrying out the present invention;

FIGURE 3 is a section on an enlarged scale of the portion indicated in F in FIGURE 2 of the device according to the invention;

FIGURE 4 is a view similar to that of FIGURE 3,

'ice

representing another embodiment of the device according to the invention;

FIGURE 5 is a diagram of the pressure versus the time illustrating the method according to the invention.

The weapon represented in FIGURE 1 comprises substantially a tube or gun I which may slide freely in a cradle or support 2 and the rear end of which has a breech 3 with its locking system 4, said breech 3 being extended by a nozzle '5. The cradle or support 2 is also provided with a trigger handle 6-, a crutch 7 and aiming means (not shown). This weapon uses the ammunition type represented in FIGURE 2- and comprising a projectile 8 the rear portion of which engages a case 9 containing the propelling charge 10 and upon the bottom 11 of which is secured, outside the case, a counter-recoil charge 12 including a priming charge 13.

In this type of weapon, the firing and the combustion of the propelling charge 10 cause the ejection of the projectile 8 together with the recoil of the tube or gun 1 moving axially in the cradle 2. The extent of said recoil, indicated in R in FIGURE 1, is controlled by the counterrccoil charge 12 the combustion of which, in addition to its braking action, is also used for bringing the gun I to the firing position. Thus, in that type of weapon, it is essential to provide for a perfect synchronization of the firings of the propelling charge 10 and the counter-recoil charge 12. Heretofore, relatively intricate and delicate electrical systems have been used to ensure this synchronize: tion. By carrying out the method according to the present invention, it is now possible to avoid said intricate and expensive synchronization devices and to substitute particularly simple and efiicient means therefor.

This may be realized by carrying on the method according to the invention which, in that particular case, comprises feeding, with expansion, a small portion of the combustion gas of charge 10 in an intermediate enclosure disposed between the enclosure defined by the case 9 and the enclosure in which is disposed the counter-recoil charge 12 and allowing the pressure within said intermediate enclosure to increase progressively up to the duly predetermined rupture pressure of one of the walls of the said intermediate enclosure, said rupture allowing the combustion gases of charge 10 to reach charge 12. This may be attained by the device indicated in F in FIGURE 2 and represented on an enlarged scale in FIGURE 3. This device comprises substantially an expansion chamber 14 defined, on one hand, by the walls and the bottom of a tubular element 15 and, on the other hand, by a lid 16 crimped in the said element 15 and in a parallel direction with the base 17 of the latter. The said base 17 is provided with a gauged opening 18. Within the chamber 14, between the lid 16 and the bottom 17, may be provided a filter 19, whereas an igniter 20 is also housed in the element 15, against the outer face of lid 16.

In another embodiment represented in FIGURE 4, the bottom of said expansion chamber 14 is truncated and ended by the said opening 18, the latter being intended to be normally closed by a ball 21.

The method according to the invention and the working of the above described device are illustrated by the time pressure diagram of FIGURE 5. In this diagram, curve C, represents the variation of pressure in accordance with the time within the tube or gun 1. This curve is well known for the intended weapon and ammunition. Curve C represents the variation of pressure in accordance with the time, for the first portion, within the expansion chamber 14 and, for the second portion, within the total volume of the expansion chamber 14, along with the volume left free by the igniter 20. Finally, curve C is the pressure curve of the counter-recoil charge 12.

The rupture pressure P of lid 16 being well determined, it is apparent that the said lid 16 will be subjected to said pressure after a combustion time t of the propelling charge 10. By the expansion of the gases in chamber 14 after their passage through the gauged opening 18, this pressure P is, at the time t substantially lower than pressure P within the gun 1. The duration of the passage of the gases of the gun I to the igniter 20 is defined by the time limited, on one hand, by the beginning of the distribution t and, on the other hand, by the time t where there is a pressure equilibrium. Thus, the amount of energy intended for starting the igniter of the counterrecoil charge is well determined and it allows a precise firing delay. Thus, the length R of the gun recoil may be perfectly fixed, whereas the return of the said gun to the firing position is only efiected after the projectile has left said gun, this time being indicated in T upon the diagram of FIGURE 5, to prevent any firing inaccuracy.

It is of course apparent that the Working of the method according to the invention is not limited to the above described device, numerous modifications of the latter being possible in accordance with each particular application of the invention.

What I claim is:

1. A time delay device comprising a first chamber containing a counter-recoil charge, a second chamber containing a propelling charge, an expansion chamber disposed between said two chambers and a passage at one end of said second chamber connecting said expansion chamber with said second chamber, the volume of said passage being substantially smaller than that of said expansion chamber, and a closure member located adjacent the opposite end of said expansion chamber and separating said expansion chamber from said first chamber, said closure member being ruptured when pressure developed in said expansion chamber, after the firing of said propelling charge, reaches a value sufiicient to rupture said closure member, said rupture occurring only after a time interval predetermined for the firing of said counter-recoil charge.

2. A time delay device as described in claim 1 wherein said expansion chamber comprises a tubular body having a bottom wall which contains said passage, said closure member constituting a lid mounted upon said body, the longitudinal axis of said passage being susbtantially perpendicular to said closure member and said closure member extending substantially perpendicularly to the longitudinal axis of said tubular body.

3. In an article of ammunition the improvement which comprises the time delay device as described in claim 1.

References Cited UNITED STATES PATENTS 2,657,630 11/1953 Blacker 10249.1 2,944,486 7/1960 Jasse 102-49.1 3,064,381 11/1962 Vilbajo 42-l 3,255,668 6/1966 Vilbajo 10238 SAMUEL W, ENGLE, Primary Examiner US. Cl. X.R. 891.703, 1.704; 102-70 

